Table 1. Memantine and Amantadine IC₅₀, (Amantadine IC₅₀)/(Memantine IC₅₀) Ratio, Ω, and ΔΔG° for Wild Type and Mutant NMDA Receptors^a.

	memantine IC50 (μM)	N	amantadine IC50 (μM)	N	IC50 ratio	Ω	ΔΔG°
WT	0.54 ± 0.03	18	41 ± 5.6	6	75
GluN1 mutants
N616Q	5.9 ± 0.5	6	490 ± 73	10	83	1.1	–0.06
N616D	14 ± 1.3	7	590 ± 21	5	41	0.55	0.35
V644N	12 ± 3.2	7	150 ± 27	8	12	0.16	1.1
V644T	0.26 ± 0.06	13	44 ± 15	13	170	2.2	–0.48
V644L	0.26 ± 0.09	15	26 ± 6.5	11	100	1.3	–0.17
A645N	240 ± 16	11	1000 ± 68	11	4.4	0.06	1.7
A645L	4.8 ± 0.4	9	53 ± 4.4	9	11	0.15	1.1
A645V	0.60 ± 0.06	9	21 ± 0.8	14	34	0.46	0.47
V656N	2.4 ± 0.2	8	94 ± 14	7	40	0.53	0.38
GluN2B mutants
N615D	1.3 ± 0.3	7	300 ± 17	9	230	3.1	–0.67
N616D	1.0 ± 0.1	6	56 ± 5.3	10	55	0.74	0.18
A639N	3.6 ± 0.4	10	140 ± 26	11	39	0.51	0.39
V640N	0.29 ± 0.03	11	12 ± 2.6	8	42	0.55	0.35
L643N	34 ± 2.7	10	750 ± 130	13	22	0.29	0.73
A644N	90 ± 2.0	9	340 ± 29	10	3.7	0.05	1.8
A644L	0.29 ± 0.07	12	3.6 ± 0.4	12	12	0.17	1.0
A644V	0.41 ± 0.05	14	10. ± 0.7	11	25	0.33	0.66

^aN= number of cells. IC₅₀ ratio = IC₅₀(amantadine)/IC₅₀(memantine). Ω = [(wild type memantine IC₅₀)(mutant amantadine IC₅₀)]/[wild type amantadine IC₅₀)/(mutant memantine IC₅₀)]. ΔΔG⁰ = RT ln(Ω), where R = 1.987 kcal·mol^–1·K^–1 and T = 298 K.